Mallaig has a few souvenir shops, two pubs, a tourist information centre and Spar and Co-op supermarkets. There is also a post office, chemist shop and ships chandlers.
In the middle of the village is the Fishmarket Restaurant serving fresh fish and some non-fish dishes. Very nice food. Alternatively, the Chlachain Inn does very nice food at reasonable prices. Their chips are great! Also, there are many other fish restaurants and other places to eat in the village.
There are many places to stay in Mallaig, though some are only open in the peak summer months.
At the large end of the scale, there is the West Highland Hotel which is a descendant of the original Station Hotel that was built to coincide with the coming of the West Highland Railway in 1901.
There are many B&B's at the cheaper end of the scale. One example is the family-run Springbank Guest House - a cheap and cheerful place just around the bay from the train station & ferry port.
See the pretty coastline between Arisaig and Morar, especially the Back of Keppoch. Both have trains from Mallaig.
See Glenfinnan Viaduct close to the Road to the Isles - as seen in the Harry Potter films!